Method of making propellant body having voids throughout body

ABSTRACT

A propellant for caseless ammunition for firearms and processes of manufacture thereof comprising at least partial dissolving of commercial nitrocellulose, wetted with a predetermined amount of a volatile wetting agent such as ethyl alcohol, by a solvent, such as acetone, to form a wet doughy mass of propellant, uniformly mixing a predetermined amount and size of removable filler particles, such as 30 percent coarse and 70 percent fine potassium nitrate particles in the wet doughy mass of propellant, forming a propellant body, and removing the wetting agent, solvent, and potassium nitrate particles to form voids throughout the propellant body.

Elnited States Patent Remaly et a1.

[ June 27, 1972 METHOD OF MAKING PROPELLANT BODY HAVING VOIDS THROUGHOUTBODY Inventors: Robert F. Remaly, Olympia Fields; William A. Abel,Joliet, both of Ill.

Victor Comptometer Chicago, 111.

Filed: Jan. 19, 1970 Appl. No.: 4,052

Assignee: Corporation,

Alexander 3,353,438 11/1967 Scanlon et al. ..264/3 Primary Examiner-CarlD. Quarforth Assistant ExaminerStephen .1. Lechert, Jr. Attorney-BruceG. Klass [57] ABSTRACT A propellant for caseless ammunition for firearmsand processes of manufacture thereof comprising at least partialdissolving of commercial nitrocellulose, wetted with a predeterminedamount of a volatile wetting agent such as ethyl alcohol, by a solvent,such as acetone, to form a wet doughy mass of propellant, uniformlymixing a predetermined amount and size of removable filler particles,such as 30 percent coarse and 70 percent fine potassium nitrateparticles in the wet doughy mass of propellant, forming a propellantbody, and removing the wetting agent, solvent, and potassium nitrateparticles to form voids throughout the propellant body 22 Claims, NoDrawings METHOD OF MAKING PROPELLANT BODY HAVING VOIDS TWOUGHOUT BODYBACKGROUND OF INVENTION l-leretofore, commercially available low energypropellant for caseless ammunition of recently developed air ignitionfirearm systems has been made by a process utilizing dry nitrocellulosebase material as described in copending applications, Ser. No. 473,556filed July 7, 1965, for Air Operated Projectile Firing Apparatus andSer. No. 785,317 filed Dec. 19, 1968, for Caseless Ammunition andPropellant and Method of Making Same. From a safety standpoint, it ispreferable to utilize wet" nitrocellulose and this invention involvesthe manufacture of air ignition system propellant from wet"nitrocellulose. Actually, United States Govermental agency regulationsrequire that various forms of nitrocellulose be transported wet withspecified amounts of volatile wetting agents such as alcohol. Inpractice, most commercial wet nitrocellulose is wetted by a mixture ofalcohol and water. Tests indicate that, at the time of utilization ofcommercial shipments of nitrocellulose, the amounts of alcohol and watervary substantially from shipment to shipment. Among the variousrequirements in the successful manufacture of a low energy propellantfor air ignition system firearm caseless ammunition, the one dominantrequirement is consistency of performance of the propellant as measuredprimarily by muzzle velocity of the caseless ammunition projectile, themaximum breech pressures generated, and the rate of burning of thepropellant as measured by the time to obtain maximum breech pressure.Thus, heretofore, the use of wet nitrocellulose in the manufacturingprocess was considered to introduce too many variables to permitconsistent manufacture of a propellant producing the desired results.However, the present invention enables the consistent manufacture ofpropellant having a controlled density and a controlled surface area.

SUMMARY OF INVENTION The invention herein disclosed resides in themanufacture of a porous propellant for caseless ammunition for firearms,presently primarily of small caliber, and more particularly for airignition system firearms, by use of a wet nitrocellulose base material.In general, the process comprises at least partially dissolving a knownquantity of wet nitrocellulose by addition of a known quantity ofnitrocellulose solvent to form a wet doughy mass of nitrocellulose,mixing a known quantity and quality of filler material in uniformdispersion throughout the wet doughy mass of nitrocellulose, forming abody of propellant from the wet doughy mass of nitrocellulose and fillermaterial, and then removing the filler material and the solvent and thewetting agent to form voids in the propellant body providing apredetermined degree of porosity. It is to be understood that allreferences to parts of ingredients in the various formulations is partsby weight.

DETAILED DESCRIPTION I. Manufacturing Processes Method A: The presentlypreferred method of manufacturing the caseless ammunition by wetprocessing comprises, in general, the steps of:

l. Grinding filler material (the presently preferred filler materialbeing solid particles of potassium nitrate) to obtain a coarse and afine particle size (the presently preferred sizes for coarse particlesbeing through size 30 sieve and on size 70 sieve, i.e. distributedbetween 0.590 mm and 0.210 mm, and for fine particles being through size200 sieve, i.e. less than 0.074 mm.) (The above sieve sizes and allsieve sizes hereinafter are U.S. Standard sieve sizes).

2. Blending the coarse and the fine size particles of filler material toobtain a filler material particle blend having predetermined amounts ofeach size (the presently preferred ratio being 70 percent fine 30percent coarse).

3. Dehydrafing water wet nitrocellulose (13.2 13.5 percent N) by passingalcohol through the nitrocellulose under pressure to obtain alcohol wetnitrocellulose having a predetermined quantity of alcohol (the presentlypreferred ratio being 25 parts alcohol to parts NC).

4. At least partially colloiding the alcohol wet nitrocellulose bymixing predetermined amounts of the alcohol wet nitrocellulose, with thenitrocellulose solvent and adding the filler material blend to obtain awet doughy mass of at least partially colloided nitrocellulose andblended filler material uniformly dispersed throughout (the presentlypreferred mixture being 100 parts dry NC wet with 25 parts alcohol, 72parts acetone solvent, 1.5 parts diphenylamine stabilizer, and parts ofa 70 percent fine30 percent coarse particle blend of potassium nitratefiller).

5. Forming the dough into individual propellant forms by anyconventional method and apparatus such as by molding or extruding andattaching each individual form to an associated projectile.

6. At least partially setting up the propellant form on the associatedprojectile (it is presently preferred to keep the propellant at roomtemperature for approximately four hours).

7. Subsequently leaching out the filler material by boiling in water(the presently preferred leaching step comprises repeated immersion ofthe propellant in boiling water 100 C.) for at least two hour intervalsfollowed by cold water rinses between boiling periods until the fillermaterial and the solvent have been substantially removed).

8. Drying the leached propellant (in the presently preferred form thepropellant is subject to hot air, 50 C., for approximately 24 hours).

Method B: An alternative method of manufacturing caseless ammunition bywet processing comprises the steps of:

l. Placing a known weight of NC having a total liquid content of waterand alcohol of approximately 25.0 percent of the weight of NC into aplastic mixing bag.

2. Adding a predetermined size and weight of KNO particles.

3. Mixing the KNO particles and the wet NC until obtaining a homogeneousmixture having no visible lumps or segregation of constituents.

4. Separately preparing a solution of acetone in the amount of 0.94 ml(0.744 grams) per gram of the volatile-free NC and diphenylamine in anamount of approximately 1.5 percent of the volatile-free NC.

5. Adding the acetone and diphenylamine solution to the NC KNO particlemixture in the mixing bag, sealing the bag, and kneading the mixture forapproximately one-half hour or until a uniform dough-like mixture isobtained.

6. Forming the dough-like mixture into a rough cylindrical charge shapedto fit an extruder cylinder associated with a mold or die cavity for .22caliber caseless ammunition.

7. Placing a 29 z 1 grain .22 caliber projectile of the type describedin copending application, Ser. No. 782,291, filed Dec. 9, 1968, for AirIgnition System Ammunition in one end of the cylinder die cavity.

8. Unsealing the bag and quickly placing the dough-like mixture into theextruder cylinder.

9. Extmding some of the doughlike mixture into the die cavity to form abody of propellant of desired size and shape attached to the rear of theprojectile.

l0. Removing the projectile and green" propellant from the die cavityand air drying the propellant.

ll. Removing the liquids and the KNO from the formed propellant body byboiling in distilled water for eight hours and changing the water everytwo hours.

ll. Ingredients A. Propellant Base Material: The base material for thepropellant is commercially available nitrocellulose having a relativelyhigh degree of nitration of between 12.5 and 13.5%

N. Nitrocellulose formed from either cotton linters or wood pulp issatisfactory and it is contemplated that other types of base materialsmay also be employed as outlined in copending application, Ser. No.785,317 filed Dec. 19, 1968, for Caseless Ammunition and Propellant andMethod of Making Same.

B. Wetting Agent: The term wetting agent" as used herein refers to thealcohol-water liquid content of the nitrocellulose utilized in theprocess and is not intended to be limited to the definition of the termas applied in general catalytic type chemical reactions although thewetting agent does appear to have some of the characteristics of suchwetting agents. Since commercially available nitrocellulose is normallywetted with alcohol and/or water in order to be safely handled andtransported, the wetting agent for the nitrocellulose may mostadvantageously be alcohol of the type used with the commerciallyavailable nitrocellulose. As will be understood by those skilled in theart, some water must be used with alcohol to prevent the alcohol fromdissolving the nitrocellulose. Ethyl alcohol is preferred but otheralcohols such as isopropyl a1- cohol may be used. While from a safetystandpoint the amount of alcohol (and/or other liquids such as water)may vary within certain limits, it appears that commercially availablewet nitrocellulose usually has between 15 and 40 percent alcohol and/orwater wetting agent volatiles associated therewith. In any event in thewet manufacturing process, it is necessary to use a known amount ofnitrocellulose and a known amount of wetting agent. Therefore, it isnecessary to process the commercially available nitrocellulose toprovide a predetermined amount of wetting agent, the presently preferredamount being 25 parts wetting agent to 100 parts nitrocellulose. It isbelieved that this ratio may be varied i 5 parts wetting agent withoutseriously affecting the ballistic performance of the porous propellant;however, it is preferable to standardize the constituents and theamounts of the wetting agent for any given formulation. One method ofstandardization is to measure and analyze the commercial wetting agentand add or subtract as necessary to achieve the desired amounts andconstituents. The presently preferred in plant method is to processcommercial water wet nitrocellulose in a standard dehydration press byforcing alcohol through the water wet nitrocellulose under pressureuntil the water is removed and the desired amount of alcohol is added.

C. Nitrocellulose Solvent: The basic requirements of the solvent arethat it be substantially inert to the filler material and sufficientlydissolve the nitrocellulose to form a workable wet doughy mass. The termdissolve," as used herein, is intended to encompass conditions variouslyreferred to in the art as gelatinizing, colloiding, etc. Since thesolvent is subsequently removed and much of it may be lost in themanufacturing process, it is highly desirable to reduce the quantityrequired. One of the advantages of wet processing is that the amount ofsolvent has been reduced as compared with the amount of solvent requiredfor dry processing. For example, in the presently preferred form ofmanufacturing an equivalent propellant by dry processing 95 parts ofacetone solvent are required per 100 parts of nitrocellulose whereas inthe presently preferred form of wet processing only 72 parts of acetonesolvent are required. Furthermore, the amount of solvent tends to remainconstant regardless of increases in the amount of filler material usedwhich is contrary to experience with dry processing where increases inthe amount of filler required additional amounts of solvent. It isbelieved that the alcohol wetting agent, while being miscible withacetone and insoluble to the nitrocellulose, acts to promote solventaction by improving the wet ability of the nitrocellulose and increasingaccessibility of the nitrocellulose to the solvent and, hence, the rateof dissolution of the nitrocellulose. The reduction in the amount ofsolvent required is also important in relationship to shrinkage of thepropellant body. Since the greatest portion of the shrinkage occursduring the solvent removal stage of the propellant manufacture,reduction of solvent will reduce the amount of shrinkage.

D. Filler Material: It is contemplated that the tiller material may beprovided by solid particles of materials other than the preferredpotassium nitrate such as other salts like barium nitrate or sugar orthe like. The amount of filler material may be varied depending upon thedesired degree of propellant porosity. While it is contemplated thatuseful results may be obtained by using filler material in amounts ofbetween 100 to 400 parts per 100 parts of nitrocellulose, the presentlypreferred ratio is 180 parts of filler material per 100 parts ofnitrocellulose. While the exact reason is unknown, the same degree ofporosity can be obtained in wet processing with a substantially lesseramount of filler material than required in dry processing. For example,the preferred wet processing filler material ratio of 180:100 isconsiderably less than the preferred dry processing filler materialratio of 239: 100. Thus, in wet processing of nitrocellulose there is asubstantial decrease in the amount of filler material required and,hence, the cost of manufacture of the propellant.

Tests indicate that the most satisfactory results are obtained by usinga blend of coarse and fine size filler material particles. While thereason why such a blend produces better results is not exactly known, itis believed that the coarse particles produce a sufficient number oflarge size voids in the propellant to insure good ignitioncharacteristics and that the fine particles produce sufficient porosityto provide good burning characteristics while maintaining a relativelyhigh charge weight per given volume of propellant. The presentlypreferred ratio of 70 percent fine and 30 percent coarse isapproximately midway between what appears to be the most useful range of60 to percent fine and 40 to 20 percent coarse.

Another factor in wet processing is the action of an alcoholwaterwetting agent on the filler material. Tests indicate that a smallamount, eg 4 or 5 percent, of the potassium nitrate may be dissolved bythe alcohol-water mixture. This dissolution probably affects allparticle sizes of potassium nitrate but the smallest particle size wouldlikely be completely dissolved. In any event, all particle sizes areprobably reduced in the mixture of solvent, wetting agent, filler, andnitrocellulose. However, after the propellant is formed and as thewetting agentsolvent volatiles are being removed, the potassium nitratein solution probably precipitates on the remaining potassium nitrateparticles to increase the size of the particles and ultimately the sizeof the voids.

E. Stabilizer and Additives: Small amounts of diphenylamine stabilizerare used in all formulations in accordance with long establishedpractice in the propellant art. While none of the various ballisticcontrolling additives have been utilized in the various formulationsherein disclosed, it is contemplated that such additives may be used ifnecessary or desirable.

Ill. Formulations EXAMPLE 1 The presently preferred formulation is asfollows:

parts nitrocellulose 25 parts wetting agent (alcohol) 72 parts solvent(acetone) parts filler material (30 percent coarse and 70 percent finepotassium nitrate particles) 1.4 parts stabilizer (diphenylamine) Thecoarse particles are between 0.59 mm and 0.21 mm (30 and 70 sieve). Thefine particles are less than 0.074 mm (200 sieve).

Physical characteristics of propellant manufactured as in method A byuse of this formulation are: charge weights 54 to 59 mg, density 0.560to 0.625 g/cc, and Shore D hardness 40 to 60. Ballistic characteristicsof such propellant are: average velocity at 75 F. 1,095 fps to 1,140fps, at 98 percent relative humidity 1,085 fps to 1,136 fps; averagemaximum chamber pressure at 75 F. 22,000 to 30,000 psi, at 0 F. 16,600to 26,000 psi, at 98 percent relative humidity 16,700 to 22,300

EXAMPLE 2 100 parts nitrocellulose 33 parts wetting agent (28 partsalcohol and 5 parts water) 72 parts solvent (acetone) V 200 parts fillermaterial (50 percent coarse 0.149 mm 100 sieve to 0.125 mm 120 sieve and50 percent fine 0.074 mm 200 sieve to 0.044 mm 325 sieve potassiumnitrate particles) 1.5 parts stabilizer (diphenylamine) Variouspropellant batches made from this formulation by method B resulted in anaverage muzzle velocity of 1,149 i 9 feet per second and an averagemaximum chamber pressure of 28,700 2 1,500 psi when fired from a testgun at 75 F. and 50 percent relative humidity. At low temperature (i.e.F.) there was a velocity decrease of less than 50 feet per second and athigh humidity (i.e. 97 i 2 percent relative humidity) there was lessthan 40 feet per second velocity loss.

With a 57 i 1 mg charge of the formulation of Example 2, changes in thepercentage of fine particles produced the following results:

% fines coarse velocity fps Example 3 0 100 1103 Example 4 25 75 1119Example 50 50 l 149 By way of comparison, with a 57 I 1 mg charge of theformulation of Example 2 processed with 250 instead of 200 partspotassium nitrate, changes in the percentage of fines produced thefollowing results:

Charges of similar weight of the propellant of Example 2 processed with200 parts filler comprising particles of between 0.149 mm (100 sieve)and 0.125 mm 120 sieve) produced an average velocity of 1,103 feet persecond and an average chamber pressure of 13,900 psi.

EXAMPLE 1 1 Other charges of similar weight of the propellant of Example2 processed with 200 parts filler comprising 50 percent coarse particlesof between 0.149 mm (100 sieve) and 0.125 mm (120 sieve) and 50 percentfine particles of between 0.074 mm (200 sieve) and 0.0014 mm (325 sieve)produced only a slightly higher average velocity of only 1,151 feet persecond with much higher average chamber pressure of 27,500 psi.

EXAMPLE 12 100 parts nitrocellulose 32 parts wetting agent( 30 partsalochol 2 parts water) 72 parts solvent (acetone) 1 part diphenylaminestabilizer 146 parts coarse filler (potassium nitrate particles 0.125 to0.149 mm) (120 to 100 sieve) 49 parts fine filler (potassium nitrateparticles 0.044 to 0.074 mm) (325 to 200 sieve) Tests show that a chargeof this formulation weighing 57 mg will produce a muzzle velocity ofapproximately 1 ,120 fps with a maximum chamber pressure ofapproximately 25,000 psi. Comparative tests indicate an approximatestraight line relationship between charge weight and velocity as well aspressure.

1V. Physical Characteristics of Caseless Round Propellant and ProjectileThe caseless ammunition for which the propellants of this invention havebeen developed comprises a 29 grain .22 caliber projectile of the typedescribed in the aforementioned copending applications or in copendingapplication, Ser. No- 782,291 filed Dec. 9, 1968, for Air lgnitionSystem Ammunition. The ammunition has a maximum outside diameter ofapproximately 0.224 inch with a length of approximately 0.540 inch. Thedesign length of the propellant portion is approximately 0.245 inch andthe design diameter is the same as the projectile diameter ofapproximately 0.224 inch. The design volume is approximately 0.00915inch", there being an attachment post extending rearwardly of theprojectile. The actual volume of propellant varies somewhat from roundto round due to production variations such as shrinkage but the averagevolume is approximately 0.0064 inch.

V. The Propellant Parameters While the propellant is designed for use ina .22 caliber air ignition system firearm, as manufactured byDaisy/Heddon. Division of Victor Comptometer Corporation, it may bemodified for use with larger caliber firearms or for other uses asnecessary or desirable. 1n the aforementioned .22 caliber system, thepropellant is designed to provide a muzzle velocity of approximatelybetween 1,100 and 1,200 feet per second and chamber pressure ofapproximately between 20,000 psi and 30,000 psi under normal conditions,it being understood that high temperature-high humidity and lowtemperature conditions have an effect on these parameters. In general,the propellant parameters producing the desired results include a chargeweight of approximately between 45 and 65 mg, a Shore D hardness ofapproximately between 40 and 60, and a density of approximately between0.500 and 0.625 g/cc. The following examples further illustrate theeffect of variations in the propellant parameters ofnitrocellulose-filler ratio and par- 60 ticle size:

A. FORMULATIONS [Examples 13-24] NC/ Wetting agent,

KNO3, ethyl alcohol Adetone g. and water, g. DPA, g. g. Particle sizes100/180 1.5 87 through 100 on 120 seive, 70% through 140 on 200 sieve.100/200 25 1.5 01. 5 through 100 on 120 sieve, 65% through 200 on 270sieve. 100/200 25 1. 5 01.6 through 100 on 120 sieve, through 140 on 200sieve. 100/200 25 1.2 82 100% through 120 on 140 sieve. 100/200 25 1.281. 5 100% through 140 on 200 sieve. 100/200 25 1. 2 81.5 100% through100 on 120 sieve. 100/220 25 1. 5 01. 5 50% through 100 on 120 sieve,50% through 140 on 200 sieve. 100/220 25 1.0 85 50% on sieve, 50%through 200 sieve. 100/220 25 1.0 through 100 on sieve. 100/220 25 1.085 63.7% on 70 sieve, 18.8% through 70 on 100 sieve, 0.5% through 100 on120 sieve, 4.5% through 120 on sieve, 6.5% through 140 on 200 sieve.100/240 25 1. 5 01.5 70% through 100 on 120 sieve, 30% through 140 on200 sieve. 24 100/240 25 1. 5 02. 5 58.5% on 70 sieve, 17.3% through 70on 100 sieve, 5.0% through 100 on 120 sieve, 4% through 120 on 140sieve, 6% through 140 on 200 sieve 8.3% through 200 sieve.

The wetting agent of Examples 13-24 is approximately 22 parts alcoholand 3 parts water.

Illxmnnlus 13-24] Vnlncl'r1:: Bulk Time to ity, sun, (Ilmruv. vlnnsity,mux. [)l'csl'ixmnpln Nu. 1.11.5. psi. \vt., mg. gmsjcc. sum, in. sec

1, 175 24, (364 no, u 524 45 1, 114 28, 000 58. .506 41 1, 133 25, 33356. 0 480 (i2 1, 140 17, 331 65. 0 556 .30 1,153 16,000 63. 0 550 431,177 18,665 5 .554 58 1,070 1, 344 51. 5 440 .80 1, 158 18, 664 62. 0.540 .46 1, 111 12,000 63. 5 554 61 1,056 8, 665 60.0 .523 41 1,074 21,341. 40. 5 432 56 001 4, 366 50.0 436 46 In general, these resultsindicate that a high percentage of coarse particles such as found inExamples 22 and 24 substantially reduce the resultant velocities andpressures. A comparison of Examples l3, 14, 15, 16, 17, 19 and 23indicates that increasing percentages of fine particles are advantageousup to at least 70 percent but that less advantageous results areobtained with 100 percent. These and other results indicate that 60 to80 percent fine particles is probably the most advantageous particlesize range. The differences in charge weight are primarily due tovariations in porosity of the propellant. The bulk density is anapproximation based upon the volume of the propellant forming die. It isto be understood that many of the results herein disclosed are basedupon limited testing and have not been substantiated to an exact degreeby quantitative or qualitative testing. However, it is believed thatthese results are generally indicative of the results to be expectedwith the formulations disclosed. Unless otherwise specified, the resultsgiven are for similarly processed ammunition fired under similarconditions from the same test apparatus.

We claim:

1. The process of manufacturing propellant for caseless ammunitioncomprising the steps of:

l. wetting nitrocellulose with a predetermined amount of substantiallyinert volatile wetting agent;

2. at least partially dissolving the wet nitrocellulose by mixing with avolatile nitrocellulose solvent inert and miscible with the wettingagent to form a wet doughy mass of nitrocellulose, solvent, and wettingagent;

3. uniformly dispersing a removable filler throughout the wet doughymass;

4. forming the wet doughy mass into a propellant body with the removablefiller uniformly dispersed throughout;

5. removing the wetting agent and solvent and removable filler withoutsubstantially changing the form of the propellant body and therebyforming voids throughout the propellant body; and

6. drying the propellant body to provide a hard porous qriopellant forcaseless ammunition. e invention as defined 1n clarm 1 and wherein thewho by weight of wetting agent to nitrocellulose is between 1:5 and 2:5.

3. The invention as defined in claim 2 and wherein the wetting agentconsists of alcohol and water.

4. The invention as defined in claim 3 and wherein the ratio by weightof alcohol to water is between 20:3 and 30:2.

5. The invention as defined in claim 2 and wherein the wetting agentconsists primarily of alcohol.

6. The invention as defined in claim 1 and wherein there is betweenapproximately 25 and 33 parts by weight wetting agent per 100 parts byweight nitrocellulose.

7. The invention as defined in claim 1 and wherein there isapproximately 25 parts by weight wetting agent per 100 parts by weightnitrocellulose.

8. The invention as defined in claim 1 and wherein the amount of solventis in the ratio of approximately between and 120 parts by weight solventto 100 parts by weight nitrocellulose.

9. The invention as defined in claim 8 and wherein the amount is lessthan approximately 100 parts by weight solvent to 100 parts by weightnitrocellulose.

10. The invention as defined in claim 9 and wherein the amount is lessthan approximately parts by weight solvent to 100 parts by weightnitrocellulose.

11. The invention as defined in claim 1 wherein the solvent is acetonein the ratio of approximately 70 75 parts by weight acetone to 100 partsby weight nitrocellulose.

12. The invention as defined in claim 1 and wherein the ratio ofremovable filler to nitrocellulose is less than 2 to l.

' 13. The invention as defined in claim 12 and wherein the ratio isbetween 1.7 to l and 1.9 to l.

14. The invention as defined in claim 13 and wherein the ratio is 1.8 tol.

15. The invention as defined in claim 1 and wherein the removable filleris a blend of coarse and fine size particles.

16. The invention as defined in claim 15 and wherein the coarse particlesize is distributed between approximately 0.59 mm and 0.21 mm.

17. The invention as defined in claim 16 and wherein the fine particlesize is less than approximately 0.074 mm.

18. The invention as defined in claim 17 and wherein the blend consistsof approximately 30 percent coarse particles and 70 percent fineparticles.

19. The invention as defined in claim 15 wherein the blend consists ofapproximately 20 to 40 percent coarse particles and to 60 percent fineparticles.

20. The invention as defined in claim 19 and wherein the blend isapproximately 30 percent coarse particles and 70 percent fine particles.

21. The invention as defined in claim 1 and wherein the volatile solventand wetting agent dissolve some of the filler in the wet doughy mass,and wherein the volatile solvent and wetting agent are removed from thepropellant before all of the filler and some of the dissolved filler isprecipitated out in the propellant during removal of the volatilesolvent and wetting agent.

22. The invention as defined in claim 21 and wherein after forming thepropellant body isfirst air dried to remove some of the volatile solventand wetting agent, and then the propellant body is placed in boilingwater to remove the filler and any remaining volatile solvent andwetting agent.

2. The invention as defined in claim 1 and wherein the ratio by weightof wetting agent to nitrocellulose is between 1:5 and 2:5.
 2. at leastpartially dissolving the wet nitrocellulose by mixing with a volatilenitrocellulose solvent inert and miscible with the wetting agent to forma wet doughy mass of nitrocellulose, solvent, and wetting agent; 3.uniformly dispersing a removable filler throughout the wet doughy mass;3. The invention as defined in claim 2 and wherein the wetting agentconsists of alcohol and water.
 4. The invention as defined in claim 3and wherein the ratio by weight of alcohol to water is between 20:3 and30:2.
 4. forming the wet doughy mass into a propellant body with theremovable filler uniformly dispersed throughout;
 5. removing the wettingagent and solvent and removable filler without substantially changingthe form of the propellant body and thereby forming voids throughout thepropellant body; and
 5. The invention as defined in claim 2 and whereinthe wetting agent consists primarily of alcohol.
 6. The invention asdefined in claim 1 and wherein there is between approximately 25 and 33parts by weight wetting agent per 100 parts by weight nitrocellulose. 6.drying the propellant body to provide a hard porous propellant forcaseless ammunition.
 7. The invention as defined in claim 1 and whereinthere is approximately 25 parts by weight wetting agent per 100 parts byweight nitrocellulose.
 8. The invention as defined in claim 1 andwherein the amount of solvent is in the ratio of approximately between70 and 120 parts by weight solvent to 100 parts by weightnitrocellulose.
 9. The invention as defined in claim 8 and wherein theamount is less than approximately 100 parts by weight solvent to 100parts by weight nitrocellulose.
 10. The invention as defined in claim 9and wherein the amount is less than approximately 75 parts by weightsolvent to 100 parts by weight nitrocellulose.
 11. The invention asdefined in claim 1 wherein the solvent is acetone in the ratio ofapproximately 70 - 75 parts by weight acetone to 100 parts by weightnitrocellulose.
 12. The invention as defined in claim 1 and wherein theratio of removable filler to nitrocellulose is less than 2 to
 1. 13. Theinvention as defined in claim 12 and wherein the ratio is between 1.7 to1 and 1.9 to
 1. 14. The invention as defined in claim 13 and wherein theratio is 1.8 to
 1. 15. The invention as defined in claim 1 and whereinthe removable filler is a blend of coarse and fine size particles. 16.The invention as defined in claim 15 and wherein the coarse particlesize is distributed between approximately 0.59 mm and 0.21 mm.
 17. Theinvention as defined in claim 16 and wherein the fine particle size isless than approximately 0.074 mm.
 18. The invention as defined in claim17 and wherein the blend consists of approximately 30 percent coarseparticles and 70 percent fine particles.
 19. The invention as defined inclaim 15 wherein the blend consists of approximately 20 to 40 percentcoarse particles and 80 to 60 percent fine particles.
 20. The inventionas defined in claim 19 and wherein the blend is approximately 30 percentcoarse particles and 70 percent fine particles.
 21. The invention asdefined in claim 1 and wherein the volatile solvent and wetting agentdissolve some of the filler in the wet doughy mass, and wherein thevolatile solvent and wetting agent are removed from the propellantbefore all of the filler and some of the dissolved filler isprecipitated out in the propellant during removal of the volatilesolvent and wetting agent.
 22. The invention as defined in claim 21 andwherein after forming the propellant body is first air dried to removesome of the volatile solvent and wetting agent, and then the propellantbody is placed in boiling water to remove the filler and any remainingvolatile solvent and wetting agent.